Absorption refrigeration



April 15, 1941,

M. SHOELD ABSORPTION REFRIGERATION 2 Shuts-Sheet 1 Filed Oct. 15. 1937 I Ila April 15, 1941. M. SHOELD 2,238,080

ABSORPTION REFRIGERATION Filed Oct. 15. 1937 2 Sheets-Sheet 2 The chamber element l is close 1 Apr. 15, 1941 r Fl on 6 Claims.

This invention relates to improvements in ab-' sorption refrigerator means and to methods of operating the same.

One object of the present invention is to pro vide an improved absorption refrigerator system. Another object is to provide a simple, positive, automatic control means for the flow of the absorption liquid from the high pressure side to the I low pressure side in the system. Still another object is to provide an eflicient absorption means of low cost provided with means for positive recirculation of the absorption liquid. A further object is to provide means for absorbing gas in a liquid in a substantially noiseless manner.

a preferred embodiment of the invention is illustrated. in the accompanying drawings in which,

Figure l is a vertical sectional view showing an arrangement of the interior and exterior features of an absorber;

Figure 2 is a horizontal cross section of the absorber taken on line 2-4 of Figure 1;

Figure 3 is a sectional view of a valve mechanism employed in the apparatus; and

Figure 4 is an elevational view, partly in section, of a complete refrigerator system,

Referring to Figure 1, the apparatus shown includes a chamber element l which may be cylindrical as illustrated or of any desired shape. at each end by closure elements 2 and 3, a d is leak-proof against gas and liquid. A pipe or inlet means t ior liquid for absorbing gas extends downwardly through the top 2 a relatively short distance into the chamber 5 formed by the element l. The pipe 4 is preferably rigidly held in position in line with the longitudinal axis of the cylinder 5.

ll. valve mechanism, shown in detail in Fig. 3, is provided adjacent the inner end i of the pipe t. it valve made from a rod, tapers to about a to" point at its lower end. The conical surface or the tapering end 8 of the valve 7 rests on a sent it within the pipe l. In a slot l0 iced by the split end of the pipe Man oceantric disc ll pivots on a pin it. The disc III is attached to or integral with a lever arm it which in t is connected at It by means of a pin to one end of a lug It. The opposite end of the lug it is plvotally connected at It to a float ll which may surround the pipe 4 as shown.

A rod it occupies the bore 19 of the pipe 4 below the seat 9. The rod l8 is-loose-fitting, and its lower end 20 rests freely on the edge of the eccentric disc ll. The upper end ii of the rod it is substantially at all times in contact with the lower pointed end of the valve l, even when the valve is in its closed position. When the lever arm I3 is lowered (from the position shown in Fig. 3) by the loweringof the float ll, the

eccentric disc ll forces the rod l8 upwardly,

thereby unseating the valve 1. An upward movement of the' float ll results in the raising of the lever l3 and lowering of the rod l8 and hence the reseating of the valve 1. Openings 22 in the bore l9 just below the seat 9 permit pas.. sage of liquid into the chamber when the valve is raised from its seat. Some liquid may also pass downwardly between the rod l8 and the wall of the bore l9.

Other means or other forms of float valves may be used for automatically controlling the influx of liquid into the chamber 5. A preferred form has been described above.

A pipe 25 is supported in a vertical position in the chamber 5 and is spaced from the walls thereof. The pipe 25 is preferably positioned in line with the longitudinal axis of the cylinder. I and is of substantial length. The lower end of the pipe 25 is provided with a flare it. A pipe 21 for introducing gas into the chamber 5 has its open end 28 adjacent the opening of the flared end of the pipe 25. Gas passing through the inlet 21 automatically causes circulation of the liquid in the chamber 5 upwardly through the pipe 25 and downwardly outside this pipe. Any means for mixing the gas and liquid to bring about absorption thereof may be employed but automatic means and particularly the means shown are preferred because besides making pos-' slble automatic and positive circulation of the liquid, such means operates noiselessly.

An outlet pipe 29 for liquid containing absorbed gas isconnected to the chamber 5 adjacent the bottom thereof.

Means are provided for dissipating the heat developed in the chamber 5. Forthis purpose copper cooling fins 30 may be placed on opposite sides of the cylinder l and attached to the latter by means of bolts 3i and nuts 32. The fins 30 are spaced apart by aluminum spacers 3d.

The above-described apparatus may be used I gas is then drawn into an absorber to form strong ammonia solution for re-use in the cycle. Some systems employ a so-called inert gas in admixture with the ammonia on the low pressure side of the cycle to equalize the total pressure between the high pressure side and the low pressure side. The absorber herein disclosed and claimed is particularly suited for use in a cycle where no inert gas is used.

In fact, a highly efllcient system may be provided by connecting the pipe 29 of the apparatus shown in Figure 1 to the intake 35 of a pump, such as that shown in Figure 4, designated generally by the numeral 35, and disclosed in my co-pending application Serial No. 136,211 filed April 10, 1937; by connecting the pipe 4 to the weak ammonia solution outlet of a generator, such as that included in the generator-heat-exchanger-rectifier unit 38 disclosed in my copending application Serial No. 156,792 filed July 31, 1937; and by connecting the pipe 21 to an evaporator 39.

The pump 35 comprises a tubular element 48 the upper end of which is closed. The closed end portion 4| comprises a thin metal cap around which is wound a heating coil 42 electrically connected to a timing mechanism 43 that intermittently admits current to the coil. The outside of the metal cap may or may not be heat insulated. The portion of the tubular element 48 below the coil-enclosed cap 4| is provided with vanes 44 for cooling or heat-dissipating purposes. A reservoir 45 is connected to the lower end of the tubular element 48 by a pipe 48.

In a preferred method of operating the pump, the coil 42 heats relatively easily volatilizable liquid 41 in the tube 40 and upon vaporization thereof, the liquidis forced out of the cap 4|. After a period of heating the electric current in the coil is automatically cut off and as the vapors cool and condense, the liquid in the tube 40 rises and fills the cap 4|. With alternate heating and cooling in this manner, a reciprocating action in the liquid is set up whereby ammonia solution from the absorber I is drawn into the reservoir 45 through a check valve 48 in the intake pipe 35, and is forced out of the reservoir through a check valve 49 in the outlet line 59 which con ducts the concentrated ammonia solution to the inlet of the. generator-heat-exchanger-rectimeans 59 in indirect heat exchange relation to fler unit 38. The check valves 48 and 49 are so,

regulated and function so that onthe suction stroke of the pump the valve 48 will open while the valve 49 remains closed, and on the pressure stroke of the pump the valve 49 will open while the valve 48 is kept closed.

If desired, mercury 52 may be used in the pipe and in the lower portions of the tube 48 and reservoir 45 to divide the volatilizable liquid 41 from the ammonia solution. To assist in speeding'up the heating and cooling of the liquid 41 a float 53 is kept down in the liquid by a weight at its lower end. This float, shown in dotted lines in -its upper and lower position, is made of a thin metal shell and moves freely in and out of the cap 4| with the liquid. The clearance between the float and the wall of the cap is preferably relatively small.

The strong ammonia solution entering the unit 39 passes through a coil 54 and into the rectifier portion of the unit 38 provided with a plurality of spaced plates 55 arranged to direct the ammonia solution in a zigzag path downwardly to adjacent the bottom of'the unit into the generator section heated by an electric heating coil 55. Heat insulation 56' may be provided outside the generator section and around the upper portion of the unit 38. The heated weak ammonia solution from the generator section passes upwardly through a tube 51 having its inlet end adjacent the bottom of ,the generator below the level 58 of the liquid being heated; thence through the liquid in the rectifier section; and thence through the weak ammonia outlet 31 and to the inlet 4 of the absorber I. If desired-suitable baifle means 59' may be provided in the heat exchanger means 59.

The ammonia gas separates from the solution in the rectifier and generator sections and passes upwardly through the unit 38, and to a condenser 58 in substantially dry form. From the condenser the ammonia passes through an expansion valve 6|, and then through the evaporator 39, through the pipe 21 and into the bottom of the absorption chamber 5 whereupon absorption of the ammonia gas takes place. (The condenser 69, expansion valve 5| and evaporator 39 are shown diagrammatically in the drawings.)

The strong ammonia solution is withdrawn through the pipe 29; the liquid level 52 in the absorber l descends slightly and with it the float |'l. As the float l1 descends. the valve I (Fig. 3) in the pipe 4 is opened and-the weak ammonia solution from the generator means or high pressure side of the system enters the chamber 5 of the absorber. The rate at which strong ammoniasolution is withdrawn through pipe 23 governs the rateat which weak ammonia solution is permitted to enter the chamber 5 through the pipe 4. Thus the normal level of liquid in the chamber 5 is maintained substantially constant. As the liquid level rises, the valve 1 is seated by gravity and by the pressure in the high pressure side of the system.

Since the pressure differential between thehigh and the low pressure sides of the system is about 200 pounds per square inch, a small valve-opening as well as a high leverage from the float IT to the rod l8 are provided so that the valve 1 pushes up with ease. The lever arm l3 and the float l'l may be so mounted that the lever arm l3 may be moved through an arc of as much as about Besides controlling the flow of liquid from the high pressure side to the low pressure side, a coni vtrol of the-liquid level in the generator is eil'ected by the float valve which is actuated by means of a change in the liquid level in the absorber. In the system described, the major portion of the liquid is always in the absorber l. The liquid in the unit 38 plus the liquid in the absorber I is practically all the liquid present in the system; the amount present in the condenser and in the evaporator at any time is relatively small or in fact minute. In the course of operation the weak ammonia solution return-from the generator to the inlet 4 of the absorber is always full. When a definite amount of. strong ammonia solution is taken from the bottom of the absorber and conducted to the unit 38,'an equivalent volume of weak ammonia solution automatically returns to the absorber.

The equivalent volume mentioned is of course actually smaller than the volume of the strong ammonia solution withdrawn from the absorber, because. the ammonia gas from the evaporator passes directly to the absorber,

The absorber I, when. provided for domestic refrigerators may be made of 1 inch or two inch piping, three or four. feet long. The pump 35 and the rectifier-generator-heat exchanger unit 38 mentioned above are of relatively small dimensions and these apparatus along with the absorber may be compactly arranged in a surprisingly small space. The relative sizes-of the pump, absorber and unit 38 are approximately illustrated in Fig. 4. I

aesaoso hen transferring ammonia solution in a system of approximately the above size and by means of the pump 36 from about atmospheric pressure to about 200 pounds per square inch gauge, the heating period in the cap 4| is about /2 minute and the cooling period therein is about 1% minutes, and the amount of ammonia solution transferred per hour is about three liters with an energy consumption of about 50 watt hours.

There are "several important advantages, be-

calized points. Furthermore the air lift effect eliminates all bubbling noise. It is well known that even if an ordinary pipe inlet is replaced by finely perforated meansfor bubbling gas into the liquid in an absorber, there is still some noise.

Advantage in the control of the liquid level in the generator by the liquid level in the absorber as shown, lies in the fact that the necessity of having a valve or other control device in the generator, particularly in the boiling zone thereof, is obviated. It is difllcult to maintain any moving mechanical device in a. generator on. account of the corrosive action of the ammonia solution at temperatures existing ina generator.

I claim:

1. In an absorption refrigerator system, an absorption unit comprising a relatively narrow pipe, and a second unit comprising a relatively narrow pipe having completely within its walls generator, rectifier and heat exchanger means, a conduit connecting the said heat exchanger means to the said absorption unit, the said heat exchanger means providing for the passage of liquid within.

also extending substantially along the said axis through-one end of the said absorption unit an. inlet tube having automatic valve means adjacent the inner end of the said inlet tube for automatically controllingthe flow of liquid through the said heat exchanger means from the said generator means into the said absorption unit;

2. In an absorption refrigerator, an absorption unit comprising a relatively long tubular contamer, an inlet pipe for supplying liquid to said unit and extending through an end of the said tubular container along substantially the longitudinal axis of the latter, means completely within the walls of said container for controlling the flow through said inlet pipe, the said control means comprising a. valve adjacent the inner end of the said liquid inlet pipe and a float for operating the said valve, a mixingtube comprising an open-ended pipe extending along substantially the longitudinal axis of the said tubular container, and a gas inlet pipe for injecting gas into one end of the said mixing tube to be absorbed by the said liquid.

3.. In an absorption refrigerator, an absorption unit comprising a relatively long tubular container, an inlet pipe for supplying liquid to said unit and extending through an endof the said tubular container along substantially the longitudinal axis of the latter, means completely within the walls of said container for controlling the fiow through said inlet pipe, the said control means comprising a valve adjacent the inner end. of the said liquid inlet pipe and a float for operating the said valve, a mixing tube comprising an open-ended pipe extending along substantial ly the longitudinal axis of the said tubular container, a gas inlet pipe for injecting gas into one end of the said mixing tube to be absorbed by the said liquid, anda plurality of parallel strips of metal attached to opposite sides of the said container and extending along substantially the entire length of the said container to dissipate the heat generated by mixing the said gas and liquid.

4. In an absorption refrigerator, an absorption unit comprising a relatively long tubular con-.- tainer, an inlet pipe for liquid to said unit and extending through an end of the said tubular container along substantially the longitudinal axis of the latter, means completely within the walls of said container for controlling the flow through said inlet pipe, the said control means comprising a valve adjacent the inner end of the said liquid inlet pipe and a float for operating the said valve, the said valve comprising aloosely mounted element having a conical surface normally seating on the upper end of a constricted portion provided adjacent the said inner end of the said liquid inlet pipe, 2. rod loosely mounted in, the said constricted portion of the said inlet pipe for raising and lowering the said valve by movement of the said float, and means attached to the said float for actuating the said rod; a mim'ng tube comprising an open-ended pipe extending along substantially the longitudinal axis of the said tubular container, and a gas inlet pipe for injecting gas into one end of the said mixing tube to be absorbed by the said liquid.

5. In an absorption refrigerator system, an absorption unit comprising a relatively narrow pipe, and a second unit comprising a relatively narrow pipe having completely within the latter pipe a generator, rectifier and heat exchanger means; a conduit connecting the said heatexchanger means to said absorption unit, the said heat exchanger means providing for the passage within the second-named pipe of liquid from the generator means through the said heat exchanger means to the said conduit in heat exchange relation to liquid andgas in the rectifier means, and means associated with the said conduit for controlling the fiow of liquid through the heat 81-,

changer from the generator into the absorption unit. a

6, In an absorption refrigerator system, an absorber, and a chamber unit including completely within the walls of the said chamber unit a generator, rectifier and heat exchanger means, a

' conduit connecting the said heat exchanger means to the said absorber, the said heat exchanger means providing for the passage of liquid from the generator to the absorber and in heat exchange relation within the said unit to liquid and gas in the rectifier means, and means completely within the absorber for controlling the flow of liquid through the said conduit.

MARK SHOEID. 

